If Real GDP Is $600 Billion,the Price Level Is 1

Multiple Choice

If real GDP is $600 billion,the price level is 1.2 and the velocity of money is 5,then what is the money supply?

A) $100 billion.
B) $3,600 billion.
C) $144 billion.
D) $2,500.
E) It cannot be determined from the information.